Author's Homepage:   R. C. Hibbeler
Chapter 10: Moments of Inertia
"In the last chapter, we determined the centroid for an area by consider the first moment of the area about an axis; that is, for the computation we had to evaluate an integral of the form int x dA. An integral of the second moment of an area, such as in x^2 dA, is referred to as the moment of inertia of the area. The terminology moment of inertia as used here is actual a misnomer; hover, it has been adopted because of the similarity with integrals of the same form related to mass."